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    <script>
   async function async1() {
       console.log(1);
       await async2();
       console.log(2);
   }
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       console.log(3);
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   console.log(4);
   
   setTimeout(function() {
       console.log(5);
   }, 0)
   
   async1();
   
   new Promise(function(resolve) {
       console.log(6);
       resolve();
   }).then(function() {
       console.log(7);
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   console.log(8);
   //主线程-同步： 
   //任务队列：宏任务     微任务：  
//4 1 3 6 8 2 7 5 

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